The cost of Receiver Optical Sub-Assemblies (ROSA) and Transmitter Optical Sub-Assemblies (TOSA) to a large extent is affected by the cost of packaging. The packaging cost in turn is often driven by the need to actively align the optical components within the ROSA/TOSA with high precision and within tight tolerances. Actively aligning these components also affects the cost of the manufacturing equipment, overall quality, yield, and manufacturability.
Multi-wavelength optical sub-assemblies are typically based upon demultiplexing (in the case of a ROSA) and multiplexing (in the case of a TOSA) using thin film filters (TFF) and mirrors to achieve wavelength separation or combination. However, the filters and mirrors require high precision optical alignments through active tuning. Such high precision active alignment increases assembly time and cost. The growth of data centers has increased the demand for cheaper and more compact optical sub-assemblies.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.